Combined effect of expansive, shrinkage reducing and hydrophobic admixtures for durable self compacting concrete

This paper presents the results of an investigation carried out to develop white self-compacting concretes (SCCs) especially devoted to durable architectural structures. In fact, shrinkage-free SCC mixtures were studied, obtained by combining CaO-based expansive agent and shrinkage reducing admixture. Also a hydrophobic admixture was added to SCC in order to preserve the white surface from the growth of micro-organisms as well as to increase concrete durability. Rheological tests were carried out on cement pastes, as well as on fresh SCCs, containing the three admixtures in order to study their influence (alone or in combination) on cement paste and concrete rheology. Also thermogravimetric analysis was carried out on cement pastes in order to evaluate the influence of various admixtures on portlandite solubility. Hardened SCCs were characterized by means of compression tests, free dying shrinkage, and restrained expansion measurements.